This application relates to the art of locks and, more particularly, to locks for securing a sliding door in a closed position. The invention is particularly adapted for use on railway box car doors which are mounted for sliding or rolling movement along a door track.
The door lock of the present application involves certain improvements to the door lock disclosed in U.S. Pat. No. 3,279,839 to Madland issued Oct. 18, 1966, the disclosure of which is incorporated hereinto by reference.
The door lock described in the foregoing U.S. Pat. No. 3,279,839 includes a bracket secured to a door jamb or to an upright edge portion on a secured auxiliary door of a double sliding door arrangement. The bracket includes vertically-spaced upper and lower sleeves with substantially vertical aligned upper and lower openings therethrough. A hasp is movably attached to a movable door and includes a sleeve portion with an opening therethrough. The hasp is positionable so that its sleeve portion is located between the bracket upper and lower sleeves with the hasp opening substantially vertically aligned relative to the bracket upper and lower openings in the upper and lower sleeves. A pin extends through the aligned openings for releasably securing the hasp against movement relative to the bracket.
In the lock assembly described in U.S. Pat. No. 3,279,839, the bottom end of the pin extends a substantial distance downwardly past the bottom edge of the lower sleeve. The bottom end portion of the pin has a circular hole or opening therethrough for receiving a security member, such as the wire loop of a padlock or the like. Instead of placing a rigid wire loop of a padlock or the like through the hole in the bottom end portion of the pin, it has been found that a relatively small and flexible shipper's seal is often passed through the hole in the pin. In view of the fact that such a seal extends through the hole in the pin only and not through any part of the bracket, it is often possible to deform and manipulate the shipper's seal for passing same upwardly along with the pin through the openings in the sleeves and hasp. This then allows unauthorized persons to enter the car without damaging the shipper's seal and subsequent replacement of the pin with the seal intact provides no warning or indication that the car has been entered.
The door lock disclosed in the foregoing patent also includes a pivoted cam member having a projection extending into a vertical groove included in the pin. A shoulder at the bottom of the groove cooperates with the cam member projection for preventing upward displacement of the pin through the hasp opening unless the cam member is pivoted outwardly for displacing the projection from the groove. The cam member has a curved bottom flange disposed opposite an upper wall portion of the hasp. Relatively small aligned holes through the cam member curved bottom flange and the hasp upper wall are sized for receiving a shipper's seal. This provides minimal extra security because the shipper's seal is easily broken for allowing outward pivotal movement of the cam member to displace the cam member projection from the pin groove and thereby allow displacement of the hasp away from the bracket so that the door can be opened. Due to the curved bottom flange on the cam member, it is sometimes difficult to align the hole therein with the hole in the hasp upper wall.
The lock described in the U.S. Pat. No. 3,279,839 has a pivoted lever cooperative with the hasp through a cooperating connection for moving the hasp generally longitudinally in response to pivoting movement of the lever for accomplishing initial opening movement or final closing movement of the door to which the hasp is attached. The cooperating holes in the hasp upper wall and cam member bottom flange are located intermediate the sleeves and the lever-to-hasp connection. This is a crowded area for a padlock or the like, and it has been found more desirable to locate such holes on the opposite side of the lever-to-hasp connection from the sleeves.
In the lock of the U.S. Pat. No. 3,279,839, the pin receiving openings in the hasp and sleeves are rectangular and the pin has a rather large cross-section to closely occupy the openings while providing a pin front wall which is wide enough to have a transverse hole for receiving a padlock wire or the like without unduly weakening the pin front wall around the hole.
In view of the foregoing circumstances, it has been considered generally desirable to have a lock of the type generally described in the U.S. Pat. No. 3,279,839 arranged in such a manner that a shipper's seal attached to the pin could not be moved upwardly with the pin without breaking the seal. Moreover, it is also considered desirable to make it possible to use a heavy wire loop of a padlock through the cam member flange and upper wall of the hasp. It is further considered desirable to revise the shape of the hasp and sleeve openings to allow reception of a wide pin front wall while reducing the width of the pin rear wall. The subject invention meets these needs and others to provide an improved door lock structure.